利用磷石膏开发替代水泥的早强充填胶凝材料

摘要

金川矿山周边堆放有大量的固体废弃物磷石膏,而金川矿山充填法采矿对胶凝材料有大量的需求。为了降低充填采矿成本,实现废弃物的资源化利用,保护矿山环境,以磷石膏为主要原料,进行了早强型充填胶凝材料的开发研究,并依据磷石膏基胶凝材料水化3 d的SEM图片对胶凝材料的水化机理进行了分析。结果表明,胶凝材料中生石灰、NaOH、磷石膏、芒硝的质量分数分别为4%、2%、30%和1．5%的情况下,3、7、28 d的抗压强度分别为3．46、5．57、9．56 MPa,早期强度明显超过设计要求。 SEM分析表明,磷石膏基胶凝材料水化反应生成水化硅酸钙凝胶和钙矾石对充填体的强度起着决定性的作用。该磷石膏基早强型胶凝材料可替代现场的32．5 #水泥。%There are large amount of phosphogypsum piled around Jinchuan Mine as waste rock,meanwhile the mining process of Jinchuan Mine have massive demand on cementing materials for backfilling. Early cementing materials are developed using phosphogypsum as main material,in order to reduce filling costs and convert the waste into valuable resources and im-prove mine environments. With the help of Scanning Electron Microscope ( SEM) ,the hydration mechanism of 3 d cementing materials based on phosphogypsum was analyzed. The experiment results indicated that,with the mass ratio of 4%,2%,30%, 1. 5%,early compressive strength of cementing material is 3. 46,5. 57,9. 56 MPa respectively,higher than that of designed re-quirements. SEM analysis showed that the hydrated calcium silicate gel and ettringite play a decisive role in improving the strength of filling body,through hydration reaction of the cementing material based on phosphogypsum. Early strength cementing material made from phosphogypsum can replace the current 32. 5# cement.